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为解决若干病原菌引起的西番莲茎基腐病症状类似,难从症状方面辨别病原菌的问题,采用经典方法即常规鉴定法,对引起海南省琼海市西番莲基腐的病原菌进行鉴定。配制选择性PDA、PDA、V-8、选择性V-84种培养基,对样本中的病原物进行分离、纯化,根据分离菌的各项形态特征描述和分离菌株的主要生长温度测定结果,以及有关文献提供的原理方法进行该分离菌鉴定。结果表明:①分离到1种疫霉菌菌株;②该菌株在选择性PDA、PDA、选择性V-8培养基生长的诸方面特征一样。菌落圆形均一,气生菌丝不丰富。孢子囊形态为侧梨形、柠檬形或椭圆形,基部钝圆,长×宽为24.5～44.3μm×22.8～34.5μm,冷冻后释放游动孢子,未见厚垣孢子。③菌株最低生长温度8～10℃,最适生长温度28℃,最高生长温度36～40℃。④28℃下,分离菌在V-8上日生长量为16.2mm,而在PDA上则为13.7mm。⑤该病原物疫霉菌属于[Phytophthora nicotianae Breda de Haan(parasitica Dastur)]。
In order to solve the problem that some pathogens cause similar symptoms of stem rot of passion flower, it is difficult to distinguish the pathogens from the symptoms. The classical method is used to identify the pathogens causing passion fruit rot in Qionghai City, Hainan Province. The selective PDA, PDA, V-8 and selective V-84 medium were prepared to separate and purify the pathogens in the samples. According to the morphological characteristics of the isolates, the main growth temperature of the strains was determined. As well as the principle of the literature provide the identification of the isolates. The results showed that: (1) one strain of Phytophthora was isolated; (2) the strain was characterized by the selective growth of PDA, PDA and selective V-8 medium. Colony circular uniform, aerial mycelium is not rich. The shape of sporangium is side pear, lemon or oval, the base is obtuse, the length and width are 24.5 ~ 44.3μm × 22.8 ~ 34.5μm, the zoospores are released after freezing, no chlamydospores are found. The lowest growth temperature of strains 8 ~ 10 ℃, the optimum growth temperature of 28 ℃, the maximum growth temperature of 36 ~ 40 ℃. ④ At 28 ℃, the amount of isolates grew 16.2mm on V-8 and 13.7mm on PDA. ⑤ Phytophthora infestans belong to [Phytophthora nicotianae Breda de Haan (parasitica Dastur)].